Overconfidence effect

Hypothesis assessment biases biases

The overconfidence effect is when we are more confident in our judgments than our accuracy warrants. For many types of questions, answers we rate as "99% certain" are wrong a large share of the time. We underestimate uncertainty and overestimate how much we know. Related: Dunning–Kruger effect, Personal incredulity (inverse).

Examples

  • You are very sure you know the way to a place you've only been once; when you drive, you get lost.

  • A student is certain they did well in an exam and is surprised by a low grade, because they confused familiarity with the material with mastery.

  • Experts routinely give ranges for forecasts that are too narrow; the true outcome often falls outside the range they were "90% confident" in.

  • You are sure you remember a conversation accurately, but when you check a recording or another person's account, your memory is wrong in important ways.

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